Calculating topsoil weight isn't exactly rocket science. However, it isn't exact science, either. Topsoil weight varies, depending on the type and consistency of soil and its water content. Sand is lighter than clay. Loam soil, a mixture of silt and sand, is the best soil; silt adds nutrients.

The topsoil may contain more water content due to recent rain or because of the consistency of the soil. Clay holds more water than sand, for example.

Topsoil is usually measured by the cubic metre (1.3 cubic yards). One cubic metre of topsoil in the UK weighs, generally, 1.7 tonnes, or 1,700kg (3,748lb).

Measure the length in metres of the area you will use for the topsoil.

Measure the width in metres of the area you will use for the topsoil.

Measure the depth in centimetres of the area you will use for the topsoil. Convert this measurement into fractions of a metre. For example, if the depth measures 4 centimetres, divide it by 100 to get 0.04 metres.

Multiply the length by the width by the depth of the topsoil. For example, if you measured 10m by 10m by 0.04m, you would get 4 cubic metres.

Multiply the number of cubic metres by 1.7 tonnes to find out how much topsoil you need. If it's 4 cubic metres, that would be 6.8 tonnes (14,991lb).

Select an online conversion calculator to determine cubic metres.

Enter the width in metres of the area of topsoil.

Enter the length in metres of the area of topsoil.

Enter the depth in centimetres of the topsoil.

Press the button marked "Calculate." View the approximate total in cubic metres. Remember that 1 cubic metre is roughly 1.7 tonnes of topsoil.